1. Technical Field
The present invention is related to a method of manufacturing a printed circuit board having a bump.
2. Description of the Related Art
With the development of the electronics industry, integration in semiconductor integrated circuits (IC) is dramatically increased. For example, the earlier applications of a mobile terminal in the mobile communication sector were limited to services such as voice call and SMS message delivery. However, the recent applications of the mobile terminal have gradually been expanded from basic communication services to multimedia services such as games, data transmission, digital photography using a digital camera and music/video file playback. Meanwhile, considering the portability of the mobile terminal performing the functions of mobile communication, reduction in size and weight of the mobile terminal is essentially required.
For the packaging of a semiconductor integrated circuit, formed on an upper surface of a printed circuit board are a bonding pad for connecting an electrode of an electronic component, such as a semiconductor component, and a resin layer that exposes the center portion of the bonding pad. A bump for coupling the electronic component to the bonding pad is formed on the bonding pad exposed from a solder resist.
The electronic component is mounted on the upper surface of the printed circuit board in such a way that each electrode of the electronic component is connected to a respective bump, and then they are heated by using an electric oven. By melting the bumps, the bumps and the electrodes of the electronic component can be coupled to one another so that the electronic component can be mounted on the board.
In one example of forming this kind of bump, solder paste constituted by flux and solder powder can be coated on a bonding pad by way of screen printing and then heated through the use of an electric oven. In this way, the solder powder in the solder paste can be melted so that a bump can be formed on the bonding pad.
In the conventional method for forming a bump, however, the rate of each bump formed can vary due to different temperatures distributed in the board, causing a difference in height between the bumps. Thus, in a printed circuit board, a plurality of bumps may be formed in different size, and thus a bump that has relatively smaller in height than its adjacent bump may not be connected to an electronic component at all.